(a) Field of the Invention
The present invention relates to a device and method of predicting NOx generation amount of a compression ignition engine, and more particularly, to a device and method of more accurately predicting NOx generation amount in real time using a combust pressure and driving variables of an engine without additional devices for analyzing exhaust gas or sensors for detecting the NOx amount.
(b) Description of the Related Art
As emission regulations for vehicles having an internal combustion engine becomes stricter, emission during operation of the internal combustion engine is required to be reduced. One developed method for reducing emission includes reduces emission generated in each cylinder of the internal combustion engine during combustion of an air/fuel mixture. Another developed method for reducing emission includes using a post-processing system of an exhaust gas in the internal combustion engine. The post-processing system of the exhaust gas is adapted to convert noxious materials generated at each cylinder during combustion of the air/fuel mixture into harmless materials. For this purpose, catalytic converters are used for converting carbon monoxide, hydrocarbon, and nitrogen oxide into harmless material.
In addition, to efficiently convert noxious materials using the catalytic converters of the exhaust gas, it is necessary to accurately predict the NOx (mono-nitrogen oxides) amount generated in the engine. According to conventional methods and systems, devices for analyzing the exhaust gas or sensors for detecting the NOx amount are used to accurately predict the NOx amount. However, the use of devices for analyzing the exhaust gas or the sensors for detecting the NOx amount causes an increase in overall costs. In addition, compositions in the engine exhaust gas may contaminate the devices for analyzing the exhaust gas or the sensors for detecting the NOx amount thus causing malfunction or failures of the sensors themselves.
Accordingly, a technique for predicting NOx amount has been developed. Reliability, however, may be deteriorated according to the technique due to complex calculation processes and simplified assumptions for simplifying the calculation processes. Additionally, in the conventional arts, since NOx amount is estimated based on the measured value when the engine is in a normal status, an error between a generated amount and a predicted amount may occur due to the deviation between the engines and the deviation of an environmental condition.
The above information disclosed in this section is merely for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.